Canned rotor system



y 1962 T. H. SARCHIN 3,044,434

CANNED ROTOR SYSTEM Filed Sept. 25, 1959 INVENTOR THEODORE H. SARCHIN ATTORNEYS purl 3,l d4,434 CANNED RGTOR SYSTEM Theodore H. Sarchin, 2739 N. Yucatan t., Arlington 13, Va. Filed Sept. 23, 1959, Ser. No. 841306 1 Claim. (Cl. l52) (Granted under Title 35, U.S. Eode (1352), sec. 2.66)

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes Without the payment of any royalties thereon or therefor.

This invention relates to an improved vertical axis propeller, and more particularly tothe type of propeller commonly used in cycloidal propulsion systems and commonly designated as Voith-Schneider propellers.

In accordance with prior art practice, most existing vertical axis, cycloidal or Voith-Schneider propeller systems include a recessed rotor enclosure or cavity in the hull of the ship in which a portion of the propeller actuating mechanism is located. Examples of the type of structure to which the instant invention relates will be found in Patents Nos. 1,740,820 and 2,243,865, in each of which is illustrated what has come to be known as a Voith- Schneider propulsion system. In accordance with conventional practice the propeller actuating mechanism of the Voith-Schneider propeller arrangement that is normally located within the hull recess includes large external projections resulting from bolt heads, structural ribs and blade bearing enclosures, all of which can readily be noted in the aforementioned patents. Ordinarily the space between the wall of the cavity in the hull and the rotatable propeller mechanism mounted in said cavity would be filled with the surrounding water, which would result in very large hydraulic losses due to the various protuberances on the rotary propeller mechanism and therefore the water in the cavity is usually evacuated. The

evacuation is generally accomplished by either an evacuati on vane pump of the type shown in United States Patent No. 1,740,820, which vane pump is built into the periphery of the rotary portion of the mechanism, or by separate air blowers that discharge into the cavity to force the ambient water out of the cavity by pressure. A pump system of either of the types set forth above is limited to relatively shallow draft ships where the hydrostatic head on the propeller cavity is small. For deep submergence applications, such as submarines or surface ships having a large draft, the pump system is not practical, since the pump size tends to become excessive and pressure control in the air cavity is extremely difficult to maintain particularly for a submarine subjected to great changes of depth. Another limitation of the pump system is that there is a loss of air in the cavity due to leakage when the propeller is inclined to an angle with a tangent greater than the ratio of the well depth in which the rotary mechanism is located, divided by the diameter of the rotor housing or cavity. This latter problem limits the positioning of the propeller to relatively small angles with the horizontal, thus severly restricting the shape of the hull in the general region of the propeller.

Pursuant to the instant invention, the actuating mechanism of a Voith-Schneider rotor system is provided with an enclosure or cover formed as a body of revolution that nests within a hull cavity likewise formed as a body of revolution, said rotor cover being a body of revolution of the same general shape as the rotor cavity but being slightly smaller in size. A vertical cross-section through the body of the rotor cover can be a trapezoid, a segment of either a circle, a parabola, an ellipse, or any section comprising straight line elements or curves fitting together. The two bodies of revolution, that is, the rotor well or cavity and the rotor cover, are fitted together Federated July '17, 1952 in a nesting fashion with only a small gap therebetween just sufiicient for satisfactory clearance when the rotor is turning. The two exposed surfaces of the bodies of revolution are made hydrodynamically smooth with all projections eliminated and any bolts, screws, or cover plates flush mounted. Thus it can be seen that the instant invention serves to substantially eliminate the presence of water from within the rotor cavity and also to provide the rotor itself with a hydrodynamically smooth surface, thereby materially reducing hydraulic losses that have heretofore been generated by the aforementioned irregularly shaped rotor.

It is accordingly an object of this invention to provide a cycloidal, or Voith-Schneider, type of propeller arrangement adapted to overcome the disadvantages of the prior art, as listed above.

Another object of this invention is to provide a cycloidal or "oith-Schneider propeller arrangement with means adapted to reduce the inherent hydraulical losses in the rotor area of the propeller arrangement.

A further object of this invention is to provide a cycloidal, or Voith-Schneider, propeller arrangement having a rotor portion recessed within a cavity in a ships hull, with means on said rotor portion to reduce the hydraulic losses caused by the portion of the rotor within said cavity.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connect-ion with the accompanying drawing wherein:

The sole FIGURE of the drawing is an elevation View, in section, of a Voith-Schneider propeller arrangement embodying the instant invention. The structure shown in the drawing is substantially symmetrical about its axis of rotation.

Referring now to the drawing, wherein like reference characters designate like and corresponding parts therethrough, there is shown a cycloidal, or Voith-Schneider, propeller arrangement 10.

In accordance with the instant invention, the cycloidal propeller structure 10 is attached to a hull 12, extending through a hole 14 formed in said hull. The propeller structure ll) includes a base plate 16 a peripheral edge projection of which rests on suitable structure within the hull of the ship. The plate 16 is also provided with a downwardly extending annular flange 17 that extends into the hole 14, and which together with the plate 16 forms a substantially closed end cavity in the hull of the ship.

An overallpropeller rotor mechanism 18 is rotatably mounted inside the annular flange 17 and includes a plurallty of circumferentially spaced propeller blades 20. Each propeller blade 20 is rotatably mounted in a horizontal plate 22 and is provided with a vertically extending rotatable shaft 24 located Within the Wall of an en closure "26 fixedly connected to the plate 22, the said I shaft 24 having its upper end journaled in said enclosure 26. It is emphasized that each of the propellers 20 has its shaft 24 mounted in the enclosure 26, although only one such arrangement is shown in the instant drawing due to the fact that it is a sectional View. 'Each of the shafts 24, in accordance with well known practice as described in detail in the patents cited above, has a shaft rotating mechanism 28 connected to the shaft. The shaft rotating mechanism 28 is connected, centrally of the rotor 18 through a rocker arm 3th to suitable drive mechanism of a well known sort adapted to selectively move the shaft rotating mechanism 28 so as to rotate the propeller blades 21 about their respective axes in the manner that is well known in conjunction with cycloidal propeller mechanisms of the type set forth in this appliconventional and well known in the art, and an example 7 of such a mechanism will be found in each of the two patents cited above.

The rotor mechanism 18, including the plate 22 having fixedly connected thereto the propeller blade supporting structures 26, is rotated through a plate 32 fixedly connected to the individual blade shaft housing structures 26. The plate 32 is rotatably connected at its center to a fixed journal housing 34, which'in turn is connected to a mechanism housing 36 conventionally located inside the hull of the ship. v

The rotary plate 32 is. driven by a main drive shaft 38 adapted to be connected to a suitable power plant. The shaft 38 has attached thereto a bevel gear 40 which is in driving engagement with a bevel ring gear 42 rotatably mounted relative to the housing 36. The ring gear 42 is in turn fixedly connected to a substantially bell shaped flange 44 that is fixedly connected to the rotary plate 3'2. Thus it can be seen that as the shaft 38 is rotated, the beveled gear 42, the rotary flange 44 and the plate 32 are rotatably driven; and by virtue of the fixed connection of the plate 32 to the rotor 22 through the housing members 26 the entire rotor housing 18 is caused to rotate by the rotation of the aforementioned shaft 38. As mentioned above, the pitch of the respective propeller blades 20 is varied through suitable motion imparted to the rocker arm 38 by structure that is conventional and well known in the art.

In accordance with the instant invention the aforementioned rotor structure 18 is provided with a cup shaped enclosure 46 of only slightly smaller size and having the same outer shape as the annular flange 17 combined with the plate 16. Both the combination annular flange 17 and plate 16, and the rotor cover 46 are bodies of revolution and thus symmetrical about a longitudinal axis through the center thereof. In addition, the outer surface of the cover 46 is in close proximity to the annular flange 17 and the plate 16, being spaced therefrom only a distance sufficient to prevent mechanical interference therebetwcen. The cover 46 is fixedly connected to the rotor plate 22 at its lower annular edge and is fixedly connected to the flange 44, so that rotation of the ring gear 42 of course causesrotation of the rotor cover 46 along with the rotor plate 22.

As a result of providing the rotor 18 with the cover 46', substantially all water is eliminated from the cavity created by the combination of the plate 16 and the annular flange 17, the only water present being that between the outer surface of the cover 46 and the inner surface of the rotor cavity, thereby reducing the hydraulic losses which normally occur due to the interaction of the various protuberances on the plate 22 and water in the cavity.

In addition, the instant construction, including the cover46 eliminates the need for providing the ship with for submarines at any depth, and can be used in place of the prior art pump-type arrangement set forth above. The instant invention is also of course simpler and less expensive to build and maintain than the aforementioned pump systems, in view of the fact that there are very few moving parts involved. The canned rotor of this invention can be positioned at any angle up to and including 180 reversal of the normally considered upright position. This capability enables a ship designer to develop the optimum hull form for performance, unrestricted by propeller positioning.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

What is claimed is:

In a ship propulsion system for deep submergence applications in submarines and surface ships having a large draft, said system located at least partially within an open ended cavity formed in the hull of said ship, said cavity being defined as a body of revolution and having one end thereof closed and the opposite end open to ambient Water, an annular circular flange, said annular circular flange being fixedly mounted in said cavity, a rotary plate mounted adjacent the open end of said cavity within said annular circular flange, drive means for rotating said plate relative to said ship, said drive means including a drive shaft, a bevel gear, said bevel gear being attached to said drive shaft, a bevel ring gear, a bell shaped flange, said bevelring gear being fixedly connected to said bell shaped flange, said bevel ring gear being operatively driven by said bevel gear, means interconnecting said bell shaped flange with said rotary plate, a plurality of circumferentially spaced propeller blades rotatably mounted on said rotary plate for rotation therewith, a shaft for each blade, each said shaft having one end fixedly attached to one of saidpropeller blades, an enclosure for housing each said propeller shaft, each said propeller shaft being enclosed by said enclosure housing and having its other end journaled in said enclosure housing, propeller rotating means located within said cavity and connected to said respective propeller blades for rotating said blades relative to said rotary plate,

a means for pumping water out of the space between the a various mechanisms on the upper face of the plate 22 and theinside of the rotor cavity; -It is also emphasized that the instant invention by eliminating all mechanical pumping devices effectively removes all sources of operational failures such as can and have occurred with the aforementioned pumping systems. The only'power loss resulting from the enclosed or canned. rotor system, produced. in accordance with this invention is a frictional one and it has been estimated that the frictional loss at full power for a typical propeller design employing the instant invention amounts toonly about oneor two percent'of the total power.

The canned rotor system produced in accordance with.

the instantinvenn'on is completely insensitive to pressure; therefore it can be used for very deep draft vessels and a cup-shaped enclosure formed as a body of revolution concentric with said cavity and enclosing said propeller blade rotating means, said cup-shaped enclosure memher being completely smooth, the peripheral edge of said enclosure being fixedly attached in a water tight relation to said rotary plate for rotation therewith and. having an outer surface with substantially the same shape as the surface of said cavity with spaced immediately adjacent thereto within said annular circular flange providing only suificient clearance to allow rotation of said rotary plate, said cavity within said annular circular flange being completely smooth continuous surface, said plate and enclosure fixedly attached thereto, rotating relative to the wall of said cavity, thereby allowing entry of water into said cavity only within the space between the outer surface of said enclosure and the surface of said cavity, whereby hydraulic losses due to rotation of the propeller blade actuating mechanism in a water medium is prevented.

References Cited in the fileof this patent UNITED STATES PATENTS 2,850,104 Hub Sept. 2,1958 2,950,765 Magnuson Aug. 30, 1960 FOREIGN PATENTS 906,896 France Sept; 4, 1944 nan/l. 

